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PostPosted: Fri Jun 28, 2013 9:25 pm 
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Thing is, I'm anti compulsion so I don't know why he chose to be rude to me, when in terms of freedom-of-choice I'm on his side. I couldn't care less what he does with his head, and I don't think our elected representatives should be worrying about it either.

It should be a choice for the individual. I choose to wear lids, but I don't kid myself they'll save me from a truck load of anvils and pianos driving over my cranium, and I don't know anyone who thinks a small piece of polystyrene will withstand 40 tonnes atop it. For me it's just one card in the deck, and works in conjunction with good lights, always a bike in A1 mechanical condition and (in my case) international standard rider training - I do my level best to make sure I never have to put the helmet to the test.

But if you don't wear a lid, or ride at night with no lights, or ride with a skinful of cider its of absolutely no consequence to me whatsoever, so why should any non-lid wearer get so het up because I do wear a lid?


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PostPosted: Fri Jun 28, 2013 10:15 pm 
retrobike rider
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Location: Near Wendover Bucks
GrahamJohnWallace wrote:
This is an extract from the conclusions of a scientific evaluation of bicycle helmet design and effectiveness:
"Designing helmets to reduce linear acceleration suits the helmets industry which has, in
effect, made a huge investment in the theory that it is the main cause of brain injury. Because the theory is widely accepted, claims that helmets prevent injury or even save lives are plausible enough to persuade the public to buy them and politicians to pass laws to compel their use, creating an assured market for them. Finding practicable means to reduce angular acceleration is an unsolved problem, however; there is no money in it for industry."
http://www.cyclehelmets.org/papers/p787.pdf


In case any bicycle helmet designers or Australian politicians are reading this I will do my best to explain the physics of angular versus linear acceleration/deceleration for them.

In a human there is a big heavy bit called a body and a lighter bit on top called the head. Joining the two is a wobbly flexible bit called a neck. The cyclist is traveling through the air at high speed but eventually he will hit something that will slow him and his head down very quickly:

If the head slows down by rotating suddenly its is called angular acceleration and will cause the brain to rotate in the skull causing blood vessels to and nerves all around the skull to tear.
But if the head does not rotate the deceleration is called linear acceleration and generally causes brain the brain to bruise and bleed internally at the point of impact.

The human brain is good best at surviving linear acceleration/deceleration perhaps because it is what happens with most loss of balance related head impacts. However the brain is far less able to withstand angular accelerations and these are commonly associated with higher speed impacts like those when being thrown from a bicycle.

You can test this with a football by kicking it hard against a hard object or surface:
If the ball does not rotate it has been subject to linear deceleration like those that current cycle helmets are designed to cope with.

If the impact of the ball cases it to rotate it has been subject to angular acceleration on impact, where the non-rotating ball suddenly accelerates rotationally. Angular acceleration forces are usually more violent for a given impact speed and current helmet designs/standards are not designed to cope with this.

Now go our and kick some footballs onto a flat road surface to see if they rotate as they land. Alternatively, use your car, HGV or one belonging to a friendly neighbour as a target.


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PostPosted: Fri Jun 28, 2013 10:20 pm 
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Would I be better off using a head?


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PostPosted: Fri Jun 28, 2013 10:36 pm 
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Perhaps a helmet made from a black box flight recorder?


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PostPosted: Fri Jun 28, 2013 10:44 pm 
retrobike rider
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The History Man wrote:
Would I be better off using a head?

Your not kicking any footballs at my head! :shock:


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PostPosted: Fri Jun 28, 2013 10:46 pm 
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Is your name graham John Wallace ?


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PostPosted: Fri Jun 28, 2013 10:51 pm 
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GrahamJohnWallace wrote:
I've been to Runcorn but I am only rude to people I know! :?


I've been to Runcorn, but I've never been to me.


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PostPosted: Fri Jun 28, 2013 10:57 pm 
retrobike rider
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The History Man wrote:
Is your name graham John Wallace ?

Only if you promise not to kick footballs at me! :shock:

If someone does kick footballs at your head, will you be better off whilst wearing a cycling helmet? :facepalm:


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PostPosted: Fri Jun 28, 2013 11:23 pm 
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Chopper1192 wrote:
Thing is, I'm anti compulsion so I don't know why he chose to be rude to me


Then I can only assume that you are so constantly habitually rude to people that you no longer notice when are being so. Hint: don't tell people that they are being "hysterical" when they merely disagree you.

If you have merely written "What makes you say that? " then I would have been polite to you in return.

Also: being rude to other people and coming over with vapours when they give you a prod back.. NOT super manly!


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PostPosted: Fri Jun 28, 2013 11:28 pm 
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Location: Runcorn
highlandsflyer wrote:
PurpleFrog wrote:

Sorry - you are wrong. Doubly wrong in fact. But, hey - you're used to it!

...You can't that get that rate without helmets doing something that you have to be an even bigger idiot still to believe: 50% of cyclists who die have fatal toros injuries, so you won't get that 90% save rate unless helmets protect torsos!

..You might not have been bright enough to work out that this is a claim that helmets make cyclists lorry-proof - obviously you weren't, perhaps because it would involve actually knowing stuff (admittedly stuff that's in the thread, so that isn't much of an excuse) and being able to do sums - but it is. No, don't thank me!



Do you really need to be so insulting?

You live in Runcorn, so how clever are you?


Given that I know that one of the biggest research centres in the UK is here - complete with supercomputers and a couple of electron accelerators... then obviously, a lot brighter than you...


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